Sunlight distribution

Figure 3.3 Average daily sunlight distribution throughout the year (Israel) (Reproduced with permission from D. Gilead and G. Scott, in Developments in Polymer Stabilisation - 5, ed. G. Scott, Applied Science Publications, 1982, p. 100)...

The water supply authorities normally insist that (for uses other than drinking-water taps) their main should discharge into a break-pressure vessel, after which the water quality becomes the consumers responsibility. The water tank should be covered against tramp dirt and access by birds, etc., and it must be shielded from sunlight to avoid the growth of algae. Nevertheless, access must be maintained for easy inspection. The distribution pipework is preferably all plastic and lead must be avoided altogether. The use of copper is doubtful with some corrosive waters, and soldered joints in it can lead to unacceptable concentrations of lead in the water. 

This new analytical method determines the rate constant and activation energy of Kevlar s photooxidative processes. The 0.2 atm of oxygen-18-labelled environment in a solar chamber simulates the air-exposure under sunlight conditions. The technique also allows the radial 0-distribution measurement from the fiber surface toward the fiber center. The data from the accelerated experimental conditions in the solar chamber in an 02-atmosphere are differentiated from the usual daylight exposure effects. 

When ethanol was used to extract the dye, the efficiency increased to 0.71% the rationale is the higher solubility of the sensitizer in alcohol and minor association which favors a more homogeneous distribution of the anthocyanins on the Ti02 surface. However, exposure to simulated sunlight (AM = 1.5,100 mWcm 2) caused a significant decrease in efficiency after 3h, probably because alcohol favors the photocatalytic decomposition of anthocyanin. 

Specific solar radiation conditions are defined by the air mass (AM) value. The spectral distribution and total flux of radiation outside the Earth s atmosphere, similar to the radiation of a black body of 5,900 K, has been defined as AM-0. The AM-1 and AM-1.5 are defined as the path length of the solar light relative to a vertical position of the Sun above the terrestrial absorber, which is at the equator when the incidence of sunlight is vertical (90°) and 41.8°, respectively. The AM-1.5 conditions are achieved when the solar flux is 982 Wm2. However, for convenience purpose the flux of the standardized AM-1.5 spectrum has been corrected to 1,000 Wm2. 

Louis curve for June 1966 is broader than that for Los Angeles in August. This is explained by differences in sunlight intensity distribution throughout the day. 

The light absorption of rhodopsin is in the visible range, with a maximum at about 500 nm. The absorption properties of the visual pigment are thus optimally adjusted to the spectral distribution of sunlight. 

The effect of light scattering and absorption by atmospheric constituents on the intensity and wavelength distribution of sunlight at the earth s surface depends on both the nature and concentration of the gases and particles as well as the path length through... 

For example, some may have short lifetimes and/or nonuniform distributions and hence be sensitive to such factors as the location of the emissions, sunlight intensity, season, etc.)... 

Geologists in the nineteenth century deduced that the Earth has experienced several ice ages, during which the ice sheets that cover the poles today reached much farther afield. In 1930 the Serbian mathematician Milutin Milankovitch showed how changes in the shape of the Earth s orbit around the Sun could trigger an ice age by altering the seasonal distribution of sunlight at the planet s surface. There are three cyclic variations in the orbit, with periods of 23,000, 41,000, and 100,000 years. The interplay of these Milankovitch cycles produces a complex but predictable and slow variation in climate over hundreds of thousands of years. 

---